Ground, or a ground node, in integrated circuits is the reference point for other voltages to be measured. Generally, the voltage level at a ground node is 0 volts (V). Many circuits, however, have more than one ground domain or ground node wherein, for example, a first sub-circuit uses a first ground node while a second sub-circuit uses a second ground node, and the voltage level at the two ground nodes is different from one another. Similarly, a circuit may have more than one power domain having more than one power supply source providing more than one supply voltage.
Like reference symbols in the various drawings indicate like elements.